Integrated circuit devices such as processors, chipsets, or other computer silicon chips typically include debug functionality intended for use during manufacturing or testing. However, if used in production, the debug functionality may present privacy or security concerns. For example, debug functionality may expose sensitive information, allow execution of malicious code, or otherwise result in unexpected operation of the integrated circuit device.
Many integrated circuit devices therefore password-protect or otherwise control entry into debug mode. Additionally, some integrated circuit devices may include debug indicators, which typically monitor entry points into debug mode and indicate whether debug mode has been entered. Typical debug indicators are stored in volatile memory or are otherwise not available across cold reboots or other power cycles. Additionally, some debug indicators may be bypassed by malicious code using a non-monitored entry point to debug mode.